In recent years, as semiconductor devices are increasingly integrated and functionalized, deposition and etching processes are rapidly switched to corresponding dry processes.
To stably provide high quality products, real-time control is crucial to accurately grasp a state inside a chamber and keep a process in an optimum state. For this reason, a residual gas analyzer (RGA) is strongly desired.
Specifically, it is known that this type of residual gas analyzer is configured to include: a sensor unit integrally provided with a sensor part including an ion source, a mass analyzing part, and a detection part, and a spectraconverter part; and an interface part that is provided between the sensor unit and an external personal computer and cable-connected to them (see, for example, Non-patent document 1).
According to the residual gas analyzer, a residual gas introduced into the ion source first collide with thermal electrons emitted from a high temperature filament, and is consequently ionized. The generated ions are accelerated and converged by a lens to be introduced into the mass analyzing part. In the mass analyzing part, DC and AC voltages are applied to four cylindrical electrodes (quadrupole) to separate the ions by mass. The separated ions are detected as a current by a Faraday cup. The ion current is proportional to an amount of the residual gas (partial pressure), and therefore the residual gas can be measured with accuracy.    Non-patent document 1: Ultracompact residual gas analyzer “PresssureMaster RGA series”, (Toru Ikeda, Special issue paper, Horiba Technical Reports, No. 28, p. 12-15, March 2004, Horiba, Ltd.)